Asteroids like Oumuamua enter our solar system about once a year, these scientists said. But they are hard to trace and had not been detected until now, thanks to stronger telescopes.

The detection suggests this object had been wandering through our galaxy, the Milky Way, unattached to any star system for hundreds of millions of years before it ran into ours.

“For decades we’ve theorized that such interstellar objects are out there, and now - for the first time - we have direct evidence they exist,” said Thomas Zurbuchen, associate administrator for NASA’s Science Mission Directorate in Washington. “This history-making discovery is opening a new window to study formation of solar systems beyond our own,” he added.

The asteroid was detected by a telescope in Hawaii. Oumuamua means messenger in Hawaiian.